cu-arpa.dietz@Cornell.ARPA (08/19/84)
Perhaps a better way to make very efficient photovoltaic cells would be
to use linear organic conductors, such as polyacetylene. In these
polymers conductivity along the polymer axis can be orders of
magnitude higher than across it.
I propose attaching charged sidechains to the polymer so the electric
field along the polymer varies in a sawtooth pattern:
-
.... ....
.... . .... .
.... . .... .
.... .... .. etc.
+
A moderate right-to-left eletric field will flatten the shallow parts
of this curve, causing current to flow. The same field with polarities
reversed will generate a smaller current, since electrons will have to
tunnel through the steep parts. The polymer will act as a rectifier.
Organic conducting polymers can be grown electrochemically, so it may
be possible to plate out solar cells from a solution of monomers.
3M has a space shuttle experiment lined up to investigate growing
organic polymer films in zero-G. These cells would probably not be too
useful in space, though, because polyacetylene loses conductivity
rapidly when exposed to radiation (since one break destroys an entire
chain).
Polyacetylene battery: I thought these things had major problems with
lifetime -- the polyacetylene electrodes break down too quickly.
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